Products > Test Equipment
Siglent SDG6000X series 200-500 MHz AWG's
Detlev:
--- Quote from: Detlev on April 18, 2023, 06:12:07 pm ---It's the SDG6022X, 200MHz / 2.4GSa/s
I've attached a screenshot of the unmodulated square wave. SDG to RTB with 50 Ohm termination
I can also make the spectra the same again with a 1kHz modulation
--- End quote ---
here hopefully with the correct picture
gf:
--- Quote from: Detlev on April 18, 2023, 06:33:58 pm ---Here again the spectra with 1kHz sine modulation at the 10MHz square wave carrier
--- End quote ---
Both don't look correct. IMO the sidebands below and above the 10MHz fundamental should look the same as with a 10MHz sine wave carrier PM-modulated with 1kHz sine (at least as long as the deviation and modulation frequency are low enough, so that the side bands of the square wave harmonics don't overlap - which is granted with the given frequency plan).
Detlev:
--- Quote from: gf on April 19, 2023, 10:16:55 am ---
--- Quote from: Detlev on April 18, 2023, 06:33:58 pm ---Here again the spectra with 1kHz sine modulation at the 10MHz square wave carrier
--- End quote ---
Both don't look correct. IMO the sidebands below and above the 10MHz fundamental should look the same as with a 10MHz sine wave carrier PM-modulated with 1kHz sine (at least as long as the deviation and modulation frequency are low enough, so that the side bands of the square wave harmonics don't overlap - which is granted with the given frequency plan).
--- End quote ---
The second spectrum is definitely broken. That only occurs after the delay and this is where the SDG6022X has a problem.
The first would be interesting to simulate. I'm in the process of getting used to Octave.
Detlev:
I once tried to upload a video of this problem to Youtube. Here you can see how the spectrum changes without doing anything and after activating the second channel, everything is ok again... for around 60 seconds
EDIT: Remove the link to the Video. Reason: The Problem ist solved in the Firmware V6.01.01.36R3
gf:
--- Quote from: Detlev on April 19, 2023, 10:27:32 am ---The first would be interesting to simulate. I'm in the process of getting used to Octave.
--- End quote ---
See plots in this earlier message.
If you want I can also attach the script which generated the plot. Eventually I went the simple DDS way, but used enough resolution and a big wavetable to keep DDS spurs below -130dBc, and the square wave gets properly band-limited with -120dB stop band attenuation at Nyquist, so that the DDS re-sampling does not noticeably suffer from aliasing.
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